Pipelines such as those in water and wastewater treatment systems are subject to unwanted air build-up and vacuum conditions that can interfere with the proper flow of water or other liquids through the pipelines. Air/vacuum valves, air release valves, and combination-type air valves are commonly installed on pipelines to prevent such air and vacuum related problems. These air valves are typically installed below grade in concrete vaults to protect the valves and the pipelines from freezing. This creates a problem because water can accumulate in the vaults during heavy rain and flooding and enter the pipelines through the air valves, thus contaminating the potable water in the pipelines.
Inflow protection devices have been developed to prevent flood water and other contaminates from entering pipelines through air valves. However, known inflow protection devices incorporate multiple float valves, check valves, etc. and are therefore complicated, expensive, and difficult to install and maintain. Moreover, known inflow protection devices are not testable or certifiable and therefore do not meet EPA, USC, or ASSC specifications for cross connection protection.